Electro-magnetic device



May 31, 1960 B. M. GORDON ELECTRO-MAGNETIC DEVICE Filed Nov. 28, 1955 INVENTOR.

BERNARD M. GORDON ATTORNEY ELECTRO-MAGNETIC DEVICE Bernard M. Gordon, Newton, Mass., assignor to Epsco,

Incorporated, Boston, Mass, a corporation of Massachusetts Filed Nov. 28, 1955, Ser. No. 549,399

1 Claim. (Cl. 335-84 vnetc devices have been provided having a ring core unit providing a closed magnetic circuit of high efficiency. The difiiculty of placing a winding about such a ring core unit has greatly increased with a reduction in size of the ring members. This has greatly increased the cost of Un rd t r ate producing such small units. These units are most use ful in conserving space when a great number are utilized as in memory networks. The small size core units also allow higher concentration of flux lines and thereby reduces the current required for energizing the electro-magnetic device.

It is therefore the principal object of this invention to provide a new and improved electro-magnetic device which may be efiiciently and inexpensively manufactured.

Another object of the invention is to provide a new and improved electromagnetic device which does not require winding machinery for its production.

Another object of the invention is to provide a new and improved electro-magnetic device providing an electrical path having numerous turns about its ring core unit.

Another object of the invention is to provide a new and improved electro-magnetic device produced by the ordinary assembling of a plurality of members without winding a conductor around a core unit.

Another object of the invention is to provide a' new and improved 'electro-magnetic device which may be produced using printed circuit techniques.

Another object of the invention is to provide a new and improved electro-magnetic device which may be made especially small and compact.

Another object of the invention is to provide a new and improved electro-magnetic device adapted for readily providing any number of windings and outlet terminals in accordance with design requirements.

Another object of this invention is to provide a new and improved electro-magnetic device which is highly reliable in operation, has a long operating life, and is rugged in construction and not readily damaged.

The above objects are achieved by providing an electromagnetic device which is toroidal in shape and comprises first and second bodies, each body having marginal and central concentric circular contact surfaces, and an an nular core space intermediate the marginal and central contact surfaces. Each of the bodies is provided with a. plurality of spaced conductive portions which extend substantially radially from the marginal contact surface to the central contact surface and about the core space.

-A ring core unit is received within the core spaces of the bodies. The core unit may be sprayed with an insulating material or otherwise prevented from contacting and shorting out the spaced conductive portions of the bodies.

The first and second bodies are provided with engaging means for securing and aligning them so that the conductive portions of the first body contact respective conductive portions of the second body to provide a helix-like electrical path passing about and progressively along the core unit. Appropriate terminal conductors are provided contacting respective conductive portions of the electro-magnetic device.

' By this construction and assembly technique, it is possible to produce a toroidal type electro-magnetic device of extremely small dimensions without the necessity for winding a conductor or conductors about the ring core unit.

The above objects as well as many other objects will become apparent when the following description of the invention is read in conjunction with the drawings, in which:

Figure 1 is a perspective view illustrating an electromagnetic device embodying the invention,

Figure 2 is an enlarged sectional view taken along the line 22 Figure 1.

Figure 3 is a sectional view taken along the line 3-3 of Figure 2.

Figure 4 is an exploded view of the device shown in Figure 1, and

Figure 5 is a detail view in perspective of several conductive elements and a terminal conductor.

Like parts are designated by like numerals throughout the several views.

The electro-magnetic device 10, comprises a first body 12, which in many respects is similar to its second body 14. The body 12 is essentially cylindrical in configuration and may be made of a plastic or other similar insulating material. The bodies 12 and 14 may be formed by machining, pressing or stamping, die-casting or any other suitable method.

The body 12 has an outer end 11 and a contact end 13. The contact end of the body 12 is provided with a circular contact surface 16 and a central circular contact surface 18. The contact surfaces 16 and 18 are concentric and separated by an annular concentric recess or groove 20 of substantially rectangular cross-section providing a core space.

The body 12 is provided with a plurality of spaced conductive portions 22 which extend substantially radially from the marginal contact surface 16 to the central contact surface 18 and within the recess 20 about the core space. The conductive portions 22 of the body 12 do not contact each other. The portions 22 may be made by painting or depositing a conductive material at the desired locations or by inserting thin metallic strips or elements 22 shown in Figure 5 with their contact ends 24, 26 respectively engaging the marginal and central contact surfaces 16 and 18, while their U shaped central portions 28 extend within the recess 20 and about the core space. 1

A plurality of terminal conductors 30, may be provided for contacting appropriate ends 24 of selected conductive elements 22. The terminal conductors 30 comprise an extending terminal portion 32, and a U-shaped securing and contact portion 34 adapted to be received over the ridge formed by the contact surface 16 of the body 12.

A core unit 36 having desired magnetic properties may be formed by a strip or band of sheet material which is wound to form the cylindrical configuration illustrated. The core unit 36 of course may be made in any other manner such as molding. One end of the core unit 36 is received within the recess 20 of the body 12. The size of the core unit 36 is such that it minimizes the inner space within the recess 20 for maximizing the efficiency of the electro-magnetic device 10. Before the core unit 36 is placed within the recess 20, the conductive elements 22 within the recess 20 are treated with an insulating material, or the unit 36 is coated with such an insulator on its outer surface 37 to prevent short circuiting of the conductive elements 22 by the core unit 36.

The second body 14 is substantially similar in construction to the body 12 so that much of the description given in connection with the body 12 will also be ap plicable to the body 14.

The body 14 is substantially cylindrical on configuration and has an outer end 17 and a contact end 15 adapted to engage the contact end 13 of the body 12. The contact end 15 of the body 14 is provided with a marginal contact surface 38 which is circular and concentric with a central circular contact surface 40. The contact surfaces 38 and 40 have intermediate them an annular circular recess 42 of substantially rectangular cross-section.

A plurality of spaced conductive portions or elements 44 are provided which have contact ends 46 and 48 respectively engaging the marginal and central contact surfaces 38 and 40, and an intermediate connecting portion 50 of U-shape which is received within the recess 42 passing about the core space of the body 14.

Sufficient insulation is also provided so that the second end of the core unit 36 may be received within the recess or groove 42 of the body 14 without short circuiting the conductive elements 44.

The body 14 is provided with a central tubular portion 52 having a key 54, while the body 12 is provided with a central opening 56 for receiving the tubular portion 52 and a slot 58 for engaging the key 54- of the body 14. By these means the bodies 12 and 14 may be aligned and secured to each other, as illustrated in Figures 1 and 2. The bodies 12 and 14 may be permanently secured together by applying an appropriate adhesive to the outer surface of the tubular portion 52 of the body 14. The bodies 12 and 14 may also be enclosed with a potting compound in the usual manner. When the core unit 36 is placed within the grooves 20 and 42 of the bodies 12 and 14, and the bodies 12 and 14 are fully engaged, the core unit 36 is entirely enclosed within the electro-magnetic device 10. Upon full engagement of the bodies 12 and 14, an electrical path substantially in the form of a helix is provided which passes about the core spaces formed by the grooves 20 and 42 and around the core unit 36 contained therein. The substantially helical conducting path progresses in the direction along the core spaces of the bodies 12 and 14 and core unit 36.

This electrical conductive path is accomplished by equally spacing the conductive elements 22, 44 Within their bodies 12, 14 and aligning the bodies 12 and 14 so that the conductive elements 22 are staggered with respect to the conductive elements 44. Since the ends 24, 26 of the units 22 extend in opposite directions as do the ends 46, 48 of the unit 44, the contact ends 24, 26 of the conductive elements 22 contact the respective ends 46, 48 of the units 44 which are stagger spaced on its opposite sides. This is clearly illustrated in Figure 3 Wherein the numerals 60 indicate the contacts made by the contact ends 24, 46 of respective conductive elements 22, 44, while connections 62 are made by the ends 26, 48 of the respective conductive elements 22, 44.

The terminal conductors 30 by making contact with the elements 22, 44, provide output and input terminals for the device 10. The elements 30 when made of a non-conductive material also serve to interrupt the helical winding formed by the conductors 22, 44. Also by placing an insulating coating on the surface 64 of the U-shaped contact portion 34 of the terminal conductor 30, the conductor 30 will connect with an element 22, while being insulated from its respective conductive element 44. This has the effect of terminating a winding at its end by insulating it from the remaining turns and bringing the ends out of the electro-magnetic unit 10 for appropriate electrical connection. When appropriate, the surface 66 of the terminal connector 30 may be provided with an insulating coating while the top surface 64 remains conductive. By these means the terminal conductors 30 by appropriate connection and spacing can form various windings about the core unit 36 as may be required in the production of the electro-magnctic device 10. Connector 30 may *be embedded in body 12 so that its surface 64 is level with surface 16.

The electro-magnetic device 10 is provided with an opening 68 which passes therethrough and may be used for mounting or supporting purposes.

Although the device 10 has been illustrated for use with a core unit 36, it may be desirable in appropriate instances to use an air core in which case a core unit such as 36 is not placed Within the unit 10. It also may be desirable to use in place of the pre-formecl core unit 36 a material which may be of liquid or plastic form and poured or set within the grooves 20 and 42 of the device 10.

It also may be possible to form the conductive portions of the bodies 12 and 14 by a printing process on a fiat surface before the bodies are formed into the final configurations. It will also be apparent that although the bodies 12 and 14 are shown to be substantially similar, bodies of different shapes and configurations may be combined to form the electro-magnetic device.

Although the invention has been illustrated with regard to a single embodiment, it will be apparent to those skilled in the art, that many modifications and variations of the structure may be made without substantially departing from the spirit of the invention.

What is claimed is:

A helical inductor comprising, a first and second similar insulating bodies, each of said bodies having a groove facing the groove of the other, each of said grooves having a plurality of generally U-shaped conducting elements spaced along the length thereof with the plane of each of said elements oriented generally perpendicular to the axis of said groove, each of said U-shaped elements having first and second ends formed with tabs pointing in opposite directions generally parallel to said axis, said insulating bodies arranged in mating relationship with said first and second tabs of each of said U-shaped elements facing and normally in electrical contact with oppositely pointed tabs of axially displaced adjacent ones of said elements in the opposite groove to form said helical inductor, and further comprising a contact element between and in contact with one facing pair of tabs of respective opposed pairs of said U-shaped elements wherein said contact element has an insulated face in contact with one of said pair of facing tabs and an uninsulated face in contact with the other thereof to define an end point of said inductor and provide a terminal for connection to said end point.

References Cited in the file of this patent UNITED STATES PATENTS 1,570,948 Crouch Jan. 26, 1926 1,695,679 Berlowitz Dec. 18, 1928 2,561,972 Cedcrberg July 24, 1951 2,666,187 Ketcham Jan. 12. 1954 

